Prenylated isoflavones

Chuankamnerdkarn, M. et al., Prenylated isoflavones from Derris scandens. Heterocycles, 57, 1901, 2002. 

Huang, K.-F. and Yen, Y.-F., Three prenylated isoflavones from Erythrina variegata, Journal of the Chinese Chemical Society, 43, 515, 1996. 

Nkengfack, A.E. et al., Auriculatin 4 -0-glucoside a new prenylated isoflavone glycoside from Erythrina eriotricha, Planta Medica, 57, 488, 1991. 

Pegnyemb, D.E. et al., A new benzoylglucoside and a new prenylated isoflavone from Lophira lanceolata, Journal of Natural Products, 61, 801, 1998. 

Rao, E.V., Prasad, Y.R., and Ganapaty, S., Three prenylated isoflavones from Milletia auricu-lata. Phytochemistry, 31, 1015, 1992. 

Almost half of the isoflavonoids identified from the Leguminosae, in which prenylated isoflavones constitute >50% of the total (pterocarpanoids, rotenoids, isoflavanones, isoflavans, coumestans, 3-arylcoumarins, and coumaronochromones), exhibit a high degree of structural diversity and complexity of prenylation.8,86"148 More than half of the isoflavones are monoprenylated, whereas 40% are diprenylated, and very few are triprenyl derivatives, with prenylation at positions 6>8>3 5 >6,>2 and O-methylation at 4 >7=6=2 =3 >5 =5>8. A number of novel isoflavonoid structures with rare skeletons, as well as complex isoflavone O- and C-glycosides have recently been reported.8,148... 

Licoricone (prenylated isoflavone) Glycyrrhiza glabra, G. uralensis (liquorice) [root, rhizome] (Fabaceae) cAMP PDE (23)... 

Forty phenolic compounds have been isolated from the aerial parts. We isolated twenty-one phenolic compounds from the aerial parts collected in Heilogjang Province in northeastern China 346-348). Among these, gancaonin A (274) was isolated for the first time as a natural product and fifteen compounds, gancaonins B-E and L-V (275-289) were isolated as new compounds. Among these, gancaonins A (274), B (275), L (279), M (280) and N (281) are prenylated isoflavones. 

Tsukayama, M., T. Horie, K. Fujimoto, and M. Nakayama A Convenient Synthesis of Prenylated Isoflavones Synthesis of Licoricone and Related Compounds. Chem. Pharm. Bull. (Japan), 34, 2369 (1986). 

Legume plants also contain many Hpophilic prenylated isoflavones (10-97), which are, in comparison with the original isoflavones, more efficient defence substances against pathogenic ilicitors (microorganisms) and animal pests (phytoalexins). They arise by prenylation of isoflavone precursors by dimethylallyl diphosphate. 

Prenylated isoflavones are related to prenylated flavonoids (chal-cones and flavanones or dihydroflavones) located in mature female cones of hops Humulus lupulus, Cannabinaceae), which exhibit oestrogenic and anticarcinogenic effects. Their amount depends on the weather conditions and the hops variety. The most common compound is a chalcone xanthohumol (10-98), which does not exhibit oestrogenic activity. Its content in hop cones is around 1%. Xanthohumol is accompanied by the flavanone isoxanthohumol, which arises from xanthohumol by conversion in an acidic media during heating. Isoxanthohumol is therefore the main prenylated flavonoid in beer. At concentrations of about 10 to 100 times lower. 

A number of isoflavones exhibit, in addition to oestrogenic activity, antimicrobial activity and other toxic effects. Examples of isoflavones exhibiting antimicrobial properties are prenylated isoflavones of legumes listed in Section 10.3.3.5.1, which occur mainly on the surface of leaves and other aboveground plant parts. Examples of such compounds are wighteon and luteon, which occur in lupines Lupinus spp.) together with other related compounds. 

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